86o THE KAHN REACTION 



that the employment of the additional Kahn procedures would give clinicians further 

 information regarding the serological status of a patient. Thus, if the routine test with 

 a given serum is positive, the performance of a quantitative procedure would give the 

 number of syphilitic reacting units; if negative, the performance of the more sensitive 

 presumptive procedure might give a clue as to the possibility of syphilitic infection 

 where otherwise syphilis might not be suspected. 



The quantitative procedure is of special value in following the serological effect 

 of anti-syphilitic treatment. The blood of a patient before treatment might show, for 

 example, 240 reacting units; after the first course, 180 units; after the second course, 

 80 units; and after the third course, 20 units. The routine test would be + +++ at 

 each examination, and would give no indication as to the relation between treatment 

 and the true serum reactions. Then again, in another case, the quantitative units 

 might be reduced, let us say, from 400 to 200 units, and not be further reduced until 

 the nature of the therapy is changed. This quantitative reaction, therefore, is an im- 

 portant guide in syphilitic therapy. Furthermore, this reaction combined with the 

 routine and presumptive procedures requires less than i cc. of serum and can be com- 

 pleted within one hour from the time blood is drawn from the patient. 



The quantitative spinal fluid procedure should also prove an important aid to 

 clinicians in the treatment of neurosyphilis. Each of the various Kahn procedures has 

 its own distinctive clinical value. The combined use of these procedures should be 

 of greater value to clinicians in the diagnosis and treatment of syphilis than the use 

 of a single procedure. 



partment of Health has reported from Oct. 15, 1925, to Oct. 15, 1927, over 150,000 Kahn reactions 

 — without Wassermann tests — with satisfactory results. The Kahn test is also standard in the U.S. 

 Navy, State Department of Health laboratories of Illinois, West Virginia, and many other labora- 

 tories. 



